The distribution of high voltage to circuitry requiring the same, such as detectors in rocket and satellite-borne experiments, has presented various problems. In the past, high voltage has been distributed much the same as low voltage, i.e. with cabling, terminals, and feed-throughs, both with and without potting. However, these methods presented many problems, the most serious of which was the observance of "false counts" from the detectors due to corona and/or breakdown of high voltage at or near the terminations located at the detectors. These discharges acted as a source of noise which was coupled into the electronics and it was very difficult to determine where and why the noise was occurring. Corona was nearly always encountered at the terminals on the detector modules, a condition which was aggravated when the circuitry was introduced into a normal high humidity enviornment or partial vacuum. These terminals were also used as distribution points for furnishing the high voltage from one detector to another.
In order to attempt to avoid corona caused problems, it became necessary to place a solder-ball on each terminal. These terminals, in practice, could have several cables attached and this aspect could make the required soldering a difficult operation. The proximity of the high voltage cables and terminals to other objects at or near ground potential was also conducive to breakdown and corona problems. In the event of a failure in the high voltage supply or the circuits using the high voltage, the wiring and soldering operation required repeating in order to substitute a working unit.
As used herein, the term "pump-out" refers to the evacuation of air to avoid corona. Unrestrained pump-out means that substantially no local pressures would linger once vacuum pumping is initiated, when the unit comprising the invention is placed in space or when vacuum testing.